1. Field of the Invention
The present invention relates to a button carrier and display backlight for an electronic device, for example a button carrier and display backlight for use with an audio device such as a motor vehicle cassette radio unit.
2. Disclosure Information
Electronic devices often have a combination of user operable buttons and a display. One known way of providing such buttons is to have a plastics material button carrier, for example a moulded piece of plastic that is held in place behind a front panel or bezel. The buttons, or areas adjacent each button, may be backlit, for example being moulded in a clear plastic on which opaque or translucent paint has been applied. The backlight then is projected through the translucent paint, for example to display words, symbols or to indicate if the button is on or off.
It is often necessary to provide more than one button carrier, for example if the buttons are arranged in areas separated by the display. In one arrangement known from a motor vehicle cassette radio, a display is held on a display carrier on which light emitting diodes (LEDs) are mounted for backlighting the display; and two separate button carriers hold buttons on either side of the display carrier. Each carrier has its own printed circuit board (PCB) on which LEDs for backlighting the display or buttons.
The display may be a liquid crystal display, backlit with a convenient source of light such as an array of LEDs. A transmissive diffuser, such as frosted clear plastic material, is sometimes provided so that the light is more evenly distributed across the display. The display LEDs may be mounted on a printed circuit board, on which the display and optionally a diffuser may be clipped or otherwise held.
Therefore, it is generally necessary for a number of carriers, optical components and PCBs to be fixed, for example by means of screws, to the inner surface of the cassette radio bezel, which is in turn clipped to the cassette radio chassis. The need to have a number of separate components with associated manufacturing steps adds to the cost of the electronic device.
It would be desireable to provide a more convenient carrier arrangement in which a button portion and a display portion may be backlit.